Wednesday, February 29, 2012

Handiham World for 29 February 2012

Welcome to Handiham World.

Ice!  Are you ready?
Ice on center insulator and dipole antenna
Photo:  Ice and snow cling to the dipole at the WA0TDA station in Minnesota.  The 450 Ohm feedline and the antenna wire are carrying a coating of heavy ice, as are the nearby tree branches.

icy branches pulling on antenna wire
Photo: Iced birch tree branches pull the antenna wire down.  

ice on 450 ohm feedline
Photo:  Heavy ice coats the 450 Ohm ladder line in this close-up.

Here it comes: The annual Spring severe weather season is here in North America.  Tornadic winds hit in the southern Midwest states of Missouri and Kansas last night, while the same huge weather system brought Minnesota freezing rain and snow.  The transition from winter to summer often means that we will be visited by bad weather that can take down antennas and put stations off the air at the very time their communications capability may be needed.  This storm was well-forecast because it was being watched even as it approached the west coast from the Pacific.  Computer modeling lends a new degree of confidence in such forecasts, so it is perhaps a bit easier than ever to be ready.  

The problem for any given amateur radio operator is that forecasts cannot predict exact weather circumstances in a small geographic area. In this particular storm, heavy snow fell north and west of my location but we only got about 3 inches worth.  Our snow was preceded by rain - freezing rain - which coalesced around antenna wires and tree branches.  When the snow came, it added to the mass already collecting on the branches and wires.  This was a prescription for power outages because tree branches would inevitably begin to break under the weight of the ice and fall across power lines. The power lines themselves, if in the clear, seldom collect enough ice to fall on their own. Sure enough, this morning almost 15,000 customers were without power here in the Twin Cities. Since the storm was more severe in the northwest part of the urban area, that was the place with the most power outages. Even so, in my town there were over 400 customers without power. Our power never failed or even flickered, probably partly because of just plain luck and good switching at the power company to keep failed power lines from bringing down the entire system. One thing I looked for specifically when purchasing my property was underground power lines. I have lived in too many neighborhoods where tree branches fell across lines and cut the power in almost every severe storm.

So what can you do to keep your own antenna systems from failing under the weight of snow and ice?

Wire antennas should be installed so that they have some "give" to them. That means that if the wire should be stressed by the extra weight of ice, the antenna will be able to bend with the weight enough to avoid outright failure. There are various methods of making a wire antenna a bit more flexible. The obvious one is to make sure that when the antenna is installed that the wire is not pulled up tight. Sometimes ingenious methods can be designed to allow an antenna anchored in a tree to move freely as the tree moves in the wind. Usually unless the tree is exceptionally flexible it will be enough to simply allow enough slack in the antenna wire to make for reasonable movement.

Rigid metal antennas are another story. Most amateur radio beam antennas are made of aluminum tubing. Some types of aluminum tubing are "aircraft grade" and may flex more than standard tubing before breaking. No matter what kind of aluminum tubing is used, it is not immune to severe damage from ice loading. If the weight of the ice itself bending the aluminum doesn't break it directly, wind that comes up after the ice is coated onto the elements may very well finish the job and bring the entire structure down in pieces. I am not sure that there is any practical way to prevent this kind of damage in a beam antenna system, but perhaps someone with experience can weigh in on the matter and let us know. Few amateur radio operators have tilt over towers that can perhaps be used to bring the whole antenna down close to the ground with the elements 90° to the surface of the earth so that water will run off of them. But what happens to the horizontal portion of the tower that will then be collecting ice? It's hard to figure out how to prevent ice damage on a beam antenna system, so keep your insurance paid up.
An antenna that is coated with ice and snow will not necessarily tune correctly. When I tried using the LDG auto tuner this morning to tune my 200 foot wire antenna on a frequency that had been previously "memorized" by the tuner, it behaved exactly as if it were visiting that 75 m frequency for the very first time. The tuner cranked away for a while before finally settling on what had to be a very different combination of capacitance and inductance to allow for a reasonable standing wave ratio. Once the ice melts off the wire, the auto tuner will have to search again for a new combination as things return to normal. One thing to consider is that not all automatic tuners will be able to match an antenna that is heavily loaded with ice and snow. The operator must be aware of this and be careful not to operate with a high standing wave ratio.
The antenna wire itself is not the only thing affected by ice and snow. If you are using open wire feed line as I am, you can expect ice loading on the feed line to contribute to changes in how the antenna behaves on the air. If you use coaxial cable, your only real concern is weight of the ice on the cable itself. Any place feed line comes into the house it should have a "drip loop" so that water can drip off the bottom of the loop of feed line as the ice melts. This prevents the water from following the cable through the wall of the house and into the ham shack.

Your antenna system will be more robust if you use good quality materials to construct it in the first place. Good antenna wire may be more expensive initially, but it will be more likely to stay up under ice loading than some bargain wire. As the old saying goes, "a chain is only as strong as its weakest link". In terms of a wire antenna system, this means that a cheap insulator could easily be a failure point no matter what kind of expensive wire and feed line you use. Needless to say, you should always take the time to secure wires properly to center and end insulators so that it will not work loose under pressure as ice pulls on the wire.

Following a weather event such as high wind or icing, you should plan to inspect your antenna systems for any possible damage or tree limbs that might've fallen against the antenna wire. Any kind of antenna system should always be located well away from power lines so that a failure in either the power line or the antenna will not make one of them come in contact with the other.
Tomorrow it will be March, and that is the month that I usually think of as being the start of this severe weather transition season. Maybe it's time to take a look at that go-kit and make sure that you are ready.

For Handiham World, I'm...
Patrick Tice,
Handiham Manager

Wednesday, February 22, 2012

Handiham World for 22 February 2012

Welcome to Handiham World.

Ham radio station
Have you ever belonged to a book club or discussion group? Sometimes public libraries or local bookstores sponsor such activities. The idea is for everyone in the group to read a book and then come together to discuss it in a relaxed and cordial atmosphere. 
I started thinking about this idea of having a discussion group while I was listening to one of our Handiham nets. As luck would have it, I was also browsing through the e-mail from my local radio club and one of the messages in my inbox had a list of potential radio club program topics. The idea of the book club discussion group and the message about radio club program topics started to mix and merge in my brain. Perhaps it would be a good idea to have a discussion topic on a regular basis during one of our nets, but make it related to a particular article about ham radio, much the same as a book club would discuss a particular novel. This would be different than the trivia net in that a roundtable discussion would be essential to make it work. The norm in many amateur radio nets is for the net control station to run the net in what I will call a "linear" format. In other words, the net control station opens the net with a preamble and then follows a pattern of calling for stations to check in with traffic or announcements or just to get on the station list for that day. Once checked into the net, a station operator need not feel obligated to check in a second or third time. In fact, if the net is run in this kind of linear format, the expectation is that permission will be requested from the net control station to "re-check" because it is assumed that once a station has checked in the net will move on to each new check-in in succession.
Of course this kind of linear format will not work in a discussion net. By its very nature, a discussion requires back-and-forth dialogue as ideas and concepts are presented and then commented on by the group. If you were sitting in a room at the library or bookstore with other book club members who have read the book of the month that has been assigned for discussion, how would you prefer that the chairs be arranged? My preference would be to put them in a circle rather than in a long line along one wall of the room. Having chairs in a circle promotes discussion, and what we want in a discussion group is the interchange of ideas. It is not an accident that this kind of ham radio net is called a "roundtable". Sitting around the table encourages discussion.
So a linear format net is different in that very fundamental way from a roundtable discussion net. If you tune across the amateur radio bands and really get familiar with what is going on, you will soon learn that groups of friends meet at various places on the bands around the same time every day or evening. Most of these groups are really just informal roundtable sessions and did not have a specific net mission or formal structure. There are, however, some discussion nets that are more formal in that the discussion topic may be limited by the group to a particular interest area such as religion or aviation. What I would propose is something just a little bit different in that the discussion topic would change depending on which article is the assigned reading of the week. The net would discuss that particular article and then participants would be able to weigh in with their opinions and suggestions as well as comment on the opinions and suggestions of the other net participants.
One consideration with this kind of a targeted roundtable discussion group is that it tends to work best when there are not too many people trying to participate. If the group gets too large, this will hamper discussion because by the time everybody gets a chance to say their piece the allotted time for the net may be nearly over. As with any kind of a net, everything will run more smoothly when all of the participants know and follow the rules. Some of the basics are:
1. Always yield to the net control station.
2. Stick to the topic.
3. Be sure you have read the article before joining the net as a participant. If you have not read the article, don't bother checking in but feel free to listen.
4. Try to be as brief and concise with your thoughts as possible so that everyone will have a chance to talk.
5. Play nice! Be respectful of everyone's opinions.
6. Take notes during the discussion so that you can comment on what has been said while you are waiting for your turn.
7. Maintain good engineering standards for your station and computer system so that your audio is clean and easy to understand.
8. Be on time for the net. Remember, the discussion will begin right away so the expectation is that only the stations who are on time will participate in the discussion. Latecomers are welcome to listen to the discussion.
9. As the discussion comes to a close, be ready with ideas for the next week's topic. At that point, the net control station can ask for other ideas and see if there is any consensus about the next article to be discussed. Sometimes this will not be possible to nail down, given the limited time available on the air. In that case, an e-mail message with a topic can be sent to the discussion group participants.
10. If the net decides that the topic will be carried over into the next week or that some other follow-up needs to be done, put that in your notes to make sure that you don't forget to do whatever "homework" needs to be done before the next net session.
You can see that this is a whole different ballgame than the nets that we are used to. Most typical linear format nets require virtually no preparation and ask very little of participants. A discussion roundtable net requires a different level of commitment but at the same time can be a more rewarding experience because of the depth of your participation. Roundtable discussion nets are not for everyone, and no one need apologize if they are just not willing to commit the time and effort that this kind of net requires. I have often found myself tuning around the bands and listening to different roundtable conversations without actually participating. There is nothing wrong with doing a lot of listening – after all, you can learn a lot by listening. If a topic area seems beyond your understanding, listening is probably your best choice until you learn enough to join in. On the other hand, some people are adventuresome and jump off the highest diving board as soon as they get to the pool. "Learn by doing", they will say, and they might just be right!
This morning I enjoyed listening on 3.930 MHz.  "The Morning Group" is up here in Minnesota, but I'm sure you have similar groups located near you. Round table discussions need not be formalized with a net control station, nor do they have to have a scheduled topic. You may find this kind of informal net to be an interesting way to stay in touch with a small group of friends who share some of your interests. On the other hand, a directed net with a net control station can give a formal roundtable with a designated topic for the day just enough direction to make for a lively and fun conversation.

For Handiham World, I'm...
Patrick Tice,
Handiham Manager

Wednesday, February 15, 2012

Handiham World for 15 February 2012

Welcome to Handiham World.
Pat, WA0TDA, wearing orange hard hat, talking into microphone.
Under construction!  That's the website, and in this photo I am pictured with the bright orange hardhat that I use for antenna projects. I guess it isn't really needed for website construction, but it makes for good show biz!
But seriously, folks...  One thing the website move to the new server has done is that it has forced me to take a new, fresh look at the member pages, and more specifically the remote base instruction and installation pages.  What a mess that part of our site is!  Taking a fresh look has put me into the situation of a brand-new user, a person just getting started with the remote base. It all seemed so logical when we first posted those remote base pages, but as the remote base project grew to a second station and then a hosting project for the W4MQ software itself, each new part of the project had its own pages.  It started to get pretty confusing, but I hadn't realized just how confusing until changing the hosting service made me take a hard-nosed new look at the whole thing. 
A new user must learn about what the remote base system is about.  The software must be located on the website and downloaded.  After that, the configuration process must be completed for both W0ZSW and W0EQO.  This cannot be done until Lyle, K0LR, and I edit the configuration files on each of the remote base station host computers.  When we do that, we also need each user's Skype name.  That means that sometime early in the website instructions we need to alert users to the fact that they will need to download and install Skype if they do not already have a Skype account.  We have to ask new users what password they would like to use for the W4MQ software, so this is something that needs to be clarified in our instruction pages.  
The way I feel about it, users should not have to fight their way through the setup process because of confusing instructions.  Heaven knows there are enough products and services out there that test our patience every day, but we don't want to be one of them!

For Handiham World, I'm...
Patrick Tice,
Handiham Manager

Wednesday, February 01, 2012

Handiham World for 01 February 2012

Welcome to Handiham World.
W0ZSW to Participate in Fourteenth Annual Minnesota QSO Party!
TS-570 transceiver

The Fourteenth Annual Minnesota QSO Party is on Saturday, February 04, 2012. It is presented by the Minnesota Wireless Association. Stations will be active 8:00 AM CST (1400 UTC) Through 6 PM CST (2400 UTC). Look for Handiham HQ station W0ZSW during the QSO Party.

Because the station will be staffed by real live humans (members of the Handiham affiliated Stillwater Amateur Radio Association, SARA), the Remote Base station W0ZSW will be off line for the duration of the contest. The W0EQO repeater will be active and connected to the Handiham Conference Server.

W0ZSW Remote Base service will be restored at 6:00 PM CST (2400 UTC) on Saturday, February 4, at the end of the contest. W0EQO Remote Base at Courage North will remain in service throughout the contest.
The SARA members are also going to help us assess equipment and clean and organize the Handiham station area and storage room. We will also check the station infrastructure and prepare some of our computer equipment with digital mode software for the upcoming Minnesota Radio Camp session in June.

We hope to hear you on the air!

For Handiham World, I'm...
Patrick Tice, WA0TDA
Handiham Manager

For more information about the Minnesota QSO Party, including frequencies and rules, please visit